This is interesting. Angel is a popular LMS, though mostly over on the corporate side of the house. The company has just incorporated a wiki into their product - but they did it by adapting the open source Tiddly Wiki. They've posted the adapted code as open source on SourceForge and even contributed financially to the Tiddly Wiki project. I agree with Michael feldstein, that they should be given kudos for taking the effort to do this right.